On Thursday, Facebook warned investors that the surge of people accessing Facebook on their mobiles or tablet devices was threatening the company’s long-term financial prospects, because it had not yet worked out how to monetise that usage.

It changed its IPO filing with the US Securities and Exchange Commission to warn that, should this trend continue: “Our financial performance and ability to grow revenue would be negatively affected.”

The social network has already gone some way to try to remedy the problem by launching its own app store, but analysts said the ammendment effectively amounted to a profit warning.

Investors and shareholder groups have also raised concerns over Facebook’s dual class shareholding structure, which will allow its 28-year-old founder Mark Zuckerberg to continue running the social network as if it were a private company.